This invention relates to inert gas arc welding, and more particularly to an attachment for inert gas arc welding torches by which to prolong the protection of the weld area by inert gas until the weld area is cooled to a temperature at which it is not adversely affected by atmospheric oxygen and nitrogen.
Inert gas arc welding is well known in the art, both as non-consumable tungsten (TIG) and as consumable metal electrode (MIG) configurations. In both types, argon, helium or other inert gas is directed in a limited area around the electrode to keep the molten puddle area flooded with inert gas, to the exclusion of atmospheric oxygen and nitrogen, to prevent the formation of metal oxides and nitrides and consequent degradation of a physical and metallurgical properties of the weld. Typical illustrations of these are found in U.S. Pat. Nos. 2,777,928; 3,172,992; 3,588,424; 3,689,725; 3,826,888; 3,838,243; and 4,166,940.
In some instances, product specifications allow cleaning of the weld by grinding and wiring brushing, even though such treatment is time consuming and admits of degradation of the weld. In other instances, particularly with refractory metals, the purity of the weld must be so high that extraordinary measures must be taken to substantially eliminate the possibility of atmospheric contamination. This has been accomplished heretofore by the use of specially constructed chambers designed to house relatively small size work for welding and capable of being filled with inert gas. This is a costly, awkward and time consuming procedure. Large work pieces, incapable of being contained within such chambers, are protected by specially constructed tooling arranged to extend along and adjacent both sides of the weld line and to deliver inert gas to side line during welding. This is a costly procedure since the tooling is useable only for the particular welding job to be done. Moreover, it is a time consuming procedure and it often results in scratching or otherwise marring the workpiece.